What is the frequency and disease burden of SARI for ICU's worldwide? What are the aetiologies of ICU SARI? How are SARI patients diagnosed and managed in the ICU? What is the outcome from SARI in the ICU? Is there a difference in outcomes from SARI depending on the aetiology of the disease? Can we identify high-risk categories of SARI that could constitute a defined population for an interventional study?